Difference between revisions of "R/C2/More-Functions-in-dplyr-Package/English"
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Sudhakarst (Talk | contribs) (Created page with "'''Title of the script''': More functions in the dplyr package '''Author''': Varshit Dubey (CoE Pune) and Sudhakar Kumar (IIT Bombay) '''Keywords''': R, RStudio, dplyr, sel...") |
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'''Keywords''': R, RStudio, dplyr, select function, starts_with function, filter, rename function, mutate function, video tutorial | '''Keywords''': R, RStudio, dplyr, select function, starts_with function, filter, rename function, mutate function, video tutorial | ||
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{| border =1 | {| border =1 | ||
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|| Highlight '''movies''' in the '''Source''' window | || Highlight '''movies''' in the '''Source''' window | ||
|| '''movies data frame''' and other filtered '''data frames''' open in the '''Source''' window. | || '''movies data frame''' and other filtered '''data frames''' open in the '''Source''' window. | ||
| − | |||
We will close all the '''data frames''' except '''movies'''. | We will close all the '''data frames''' except '''movies'''. | ||
|- | |- | ||
|| Highlight the scroll bar in the '''Source''' window | || Highlight the scroll bar in the '''Source''' window | ||
| − | |||
Click on the '''movies data frame''' >> scroll from left to right. | Click on the '''movies data frame''' >> scroll from left to right. | ||
|| In the '''Source''' window, scroll from left to right. | || In the '''Source''' window, scroll from left to right. | ||
| − | |||
This will enable us to see the remaining objects of the '''movies''' '''data frame'''. | This will enable us to see the remaining objects of the '''movies''' '''data frame'''. | ||
| Line 144: | Line 140: | ||
|| Highlight '''thtr_rel_year''', '''thtr_rel_month''', '''thtr_rel_day''' in the '''Source''' window | || Highlight '''thtr_rel_year''', '''thtr_rel_month''', '''thtr_rel_day''' in the '''Source''' window | ||
|| In the data frame, we can see the variables like '''thtr_rel_day, thtr_rel_month, thtr_rel_year'''. | || In the data frame, we can see the variables like '''thtr_rel_day, thtr_rel_month, thtr_rel_year'''. | ||
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These variables provide information about the day, month and year of the theatre release of the '''movies.''' | These variables provide information about the day, month and year of the theatre release of the '''movies.''' | ||
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|| Highlight '''thtr_rel_year''', '''thtr_rel_month''', '''thtr_rel_day''' in the '''Source''' window | || Highlight '''thtr_rel_year''', '''thtr_rel_month''', '''thtr_rel_day''' in the '''Source''' window | ||
|| Let us select these three variables along with the '''title''' of all the '''movies'''. | || Let us select these three variables along with the '''title''' of all the '''movies'''. | ||
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Please note that all the theatre related variable names start with '''t h t r'''. | Please note that all the theatre related variable names start with '''t h t r'''. | ||
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* Use the built-in data set '''airquality'''. Using '''select''' function select the variables '''Ozone''', '''Wind''', and '''Temp''' in this data set. | * Use the built-in data set '''airquality'''. Using '''select''' function select the variables '''Ozone''', '''Wind''', and '''Temp''' in this data set. | ||
* Use the built-in data set '''mtcars'''. Rename the variables '''mpg''' and '''cyl '''with '''MilesPerGallon''' and '''Cylinder''', respectively. | * Use the built-in data set '''mtcars'''. Rename the variables '''mpg''' and '''cyl '''with '''MilesPerGallon''' and '''Cylinder''', respectively. | ||
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|- | |- | ||
Revision as of 16:24, 28 August 2019
Title of the script: More functions in the dplyr package
Author: Varshit Dubey (CoE Pune) and Sudhakar Kumar (IIT Bombay)
Keywords: R, RStudio, dplyr, select function, starts_with function, filter, rename function, mutate function, video tutorial
| Visual Cue | Narration |
| Show slide
Opening Slide |
Welcome to this tutorial on More functions in the dplyr package. |
|
Show slide Learning Objective |
In this tutorial, we will learn about the following functions in the dplyr package:
|
|
Show slide Pre-requisites |
To understand this tutorial, you should know,
If not, please locate the relevant tutorials on R on this website. |
| Show slide
System Specifications |
This tutorial is recorded on
Install R version 3.2.0 or higher. |
| Show slide
Download Files |
For this tutorial, we will use
Please download these files from the Code files link of this tutorial. |
| [Computer screen]
Highlight moviesData.csv and myVis.R in the folder DataVis |
I have downloaded and moved these files to DataVis folder.
This folder is located in myProject folder on my Desktop. I have also set the DataVis folder as my Working Directory. |
| Let us switch to RStudio. | |
| Highlight myVis.R in the Files window of RStudio | Open the script myVis.R in RStudio. |
| Highlight filter and arrange in the Source window | We have already learnt how to use the filter and arrange functions in the dplyr package. |
| Highlight the Source button | Run this script by clicking on the Source button. |
| Highlight movies in the Source window | movies data frame and other filtered data frames open in the Source window.
We will close all the data frames except movies. |
| Highlight the scroll bar in the Source window
Click on the movies data frame >> scroll from left to right. |
In the Source window, scroll from left to right.
This will enable us to see the remaining objects of the movies data frame. |
| Highlight movies in the Source window | To select the required variables of a data frame we will use the select function.
It helps us to select only those variables that are required. |
| Highlight title, genre, and imdb_rating in the Source window | Here, we will use the select function to select
title, genre, and imdb rating for all the movies. |
| Highlight the script myVis.R in the Source window | Click on the script myVis.R |
| [RStudio]
moviesTGI <- select(movies, title, genre, imdb_rating) View(moviesTGI) |
In the Source window, type the following command. |
| Highlight select in the Source window | The first argument in the select function is the name of the data frame. Here it is movies. |
| Highlight select in the Source window | Other arguments are the variables which we will select for all the movies. |
| Click on Save button to save the script.
Press Ctrl + Enter keys. |
Save the script and run the last two lines of code by pressing Ctrl + Enter keys simultaneously. |
| Highlight moviesTGI in the Source window | moviesTGI opens in the Source window. |
| Highlight the columns of moviesTGI in the Source window | Here, title, genre, and imdb rating of all the movies are displayed. |
| Highlight moviesTGI in the Source window | Let us close moviesTGI data frame for now. |
| Highlight movies in the Source window | In the Source window, click on movies data frame. |
| Highlight the scroll bar in the Source window | Scroll the data frame from right to left to see other columns. |
| Highlight thtr_rel_year, thtr_rel_month, thtr_rel_day in the Source window | In the data frame, we can see the variables like thtr_rel_day, thtr_rel_month, thtr_rel_year.
These variables provide information about the day, month and year of the theatre release of the movies. |
| Highlight thtr_rel_year, thtr_rel_month, thtr_rel_day in the Source window | Let us select these three variables along with the title of all the movies.
Please note that all the theatre related variable names start with t h t r. |
| Highlight the script myVis.R in the Source window | Click on the script myVis.R. |
| [RStudio]
moviesTHT <- select(movies, title, starts_with("thtr")) View(moviesTHT) |
In the Source window, type the following command. |
| Highlight start_with in the Source window | Here, we have used starts_with function.
It selects all the variables in the movies data frame, whose names start with t h t r. |
| Highlight run button in the Source window | Run the last two lines of code. |
| Highlight moviesTHT in the Source window | moviesTHT opens in the Source window.
movies with their titles and theatre release information are shown. |
| Highlight moviesTHT in the Source window | Let us close moviesTHT data frame for now. |
| Highlight movies in the Source window | In the Source window, click on movies. |
| Highlight thtr_rel_year in the Source window | Let us change the name of the variable thtr_rel_year.
For that, we will use the rename function. |
| Highlight the script myVis.R in the Source window | Click on the script myVis.R |
| [RStudio]
moviesR <- rename(movies, rel_year = "thtr_rel_year") View(moviesR) |
In the Source window, type the following command. |
| Highlight rename in the Source window | Here, we are changing the name of the variable thtr_rel_year. |
| Highlight run button in the Source window | Run the last two lines of code. |
| Highlight moviesR in the Source window | moviesR opens in the Source window. |
| Highlight the scroll bar in the Source window | In the Source window, scroll from left to right. |
| Highlight rel_year in the Source window | Observe that the name of the variable thtr_rel_year has changed to rel_year. |
| Highlight moviesR in the Source window | Let us close the data frame moviesR for now. |
| Highlight movies in the Source window | In the Source window, click on movies. |
| Highlight the scroll bar in the Source window | In the Source window, scroll from left to right. |
| Highlight critics_score and audience_score in the Source window | Suppose we want to add a new variable named CriAud to our movies data frame.
This variable should contain the difference between critics_score and audience_score. For this, we will use the mutate function. mutate function is used to add new variable and preserve existing one. |
| Highlight audience_score in the Source window | For simplicity let us remove the variables appearing after audience_score in the movies data frame. |
| Highlight the scroll bar in the Source window | In the Source window, scroll from right to left. |
| Highlight title in the Source window | We need to select the variables from title to audience_score.
For this, we will use the select function. |
| Highlight the script myVis.R in the Source window | Click on the script myVis.R |
| [RStudio]
moviesLess <- select(movies, title:audience_score) |
In the Source window, type the following command. |
| Highlight run button in the Source window | Run the current line. |
| Now, we will use the mutate function to add a new variable. | |
| [RStudio]
moviesMu <- mutate(moviesLess, CriAud = critics_score - audience_score) View(moviesMu) |
In the Source window, type the following command. |
| Highlight mutate in the Source window | Remember, we are adding a new variable CriAud in the movies data frame.
This is to store the difference of critics score and audience score. |
| Highlight run button in the Source window | Run the last two lines of code. |
| Highlight moviesMu in the Source window | moviesMu opens in the Source window. |
| Highlight the scroll bar in the Source window | In the Source window, scroll from left to right. |
| Highlight CriAud in the Source window | A new variable named CriAud is added. |
| Let us summarize what we have learnt. | |
|
Show slide Summary |
In this tutorial, we have learnt about the following functions available in the dplyr package:
|
| Show slide
Assignment |
We now suggest an assignment.
|
| Show slide
About the Spoken Tutorial Project |
The video at the following link summarises the Spoken Tutorial project.
Please download and watch it. |
| Show slide
Spoken Tutorial Workshops |
We conduct workshops using Spoken Tutorials and give certificates.
Please contact us. |
| Show Slide
Forum to answer questions |
Please post your timed queries in this forum. |
| Show Slide
Forum to answer questions |
Please post your general queries in this forum. |
| Show Slide
Textbook Companion |
The FOSSEE team coordinates the TBC project.
For more details, please visit these sites. |
| Show Slide
Acknowledgment |
The Spoken Tutorial project is funded by NMEICT, MHRD, Govt. of India |
| Show Slide
Thank You |
The script for this tutorial was contributed by Varshit Dubey (CoE Pune).
This is Sudhakar Kumar from IIT Bombay signing off. Thanks for watching. |
